TY - JOUR
T1 - Speciation and longand short-term molecular-level dynamics of soil organic sulfur studied by x-ray absorption near-edge structure Spectroscopy
AU - Solomon, Dawit
AU - Lehmann, Johannes
AU - de Zarruk, Katrin Knoth
AU - Dathe, Julia
AU - Kinyangi, James
AU - Liang, Biqing
AU - Machado, Stephen
PY - 2011/5
Y1 - 2011/5
N2 - We investigated speciation, oxidative state changes, and longand short-term molecular-level dynamics of organic S after 365 d of aerobic incubation with and without theaddition of sugarcane residue using XANES spectroscopy. Soil samples were collected from theupper 15 cm of undisturbed grasslands since 1880, from undisturbed grasslands since 1931, and from cultivated fields since 1880 in thewestern United States. We found three distinct groups of organosulfur compounds in these grassland-derived soils: (i) strongly reduced (S0 to S1+) organic S that encompasses thiols, monosulfides, disulfides, polysulfides, and thiophenes; (ii) organic S in intermediate oxidation (S2+ to S5+) states, which include sulfoxides and sulfonates; and (iii) strongly oxidized (S6+) organic S, which comprises ester-SO4-S. Th e first two groups represent S directly linked to C and accounted for 80% of thetotal organic S detected by XANES from theundisturbed soils. Aerobic incubation without theaddition of sugarcane residue led to a 21% decline in organanosulfur compounds directly linked to C and to up to an 82% increase inorganic S directly bonded to O. Among theC-bonded S compounds, low-valence thiols, sulfides, thiophenic S, and intermediate-valence sulfoxide S seem to be highly susceptible to microbial attack and may represent themost reactive components of organic S pool in these grassland soils. Sulfonate S exhibited a much lower shortterm reactivity. Th e incorporation of sugarcane residue resulted in an increase in organosulfur compounds directly bonded to C at theearly stage of incubation. However, similar to soils incubated without residue addition, theproportion of organic S directly linked to C continued to decline with increasing duration of aerobic incubation, whereas theproportion of organic S directly bonded to O showed a steady rise.
AB - We investigated speciation, oxidative state changes, and longand short-term molecular-level dynamics of organic S after 365 d of aerobic incubation with and without theaddition of sugarcane residue using XANES spectroscopy. Soil samples were collected from theupper 15 cm of undisturbed grasslands since 1880, from undisturbed grasslands since 1931, and from cultivated fields since 1880 in thewestern United States. We found three distinct groups of organosulfur compounds in these grassland-derived soils: (i) strongly reduced (S0 to S1+) organic S that encompasses thiols, monosulfides, disulfides, polysulfides, and thiophenes; (ii) organic S in intermediate oxidation (S2+ to S5+) states, which include sulfoxides and sulfonates; and (iii) strongly oxidized (S6+) organic S, which comprises ester-SO4-S. Th e first two groups represent S directly linked to C and accounted for 80% of thetotal organic S detected by XANES from theundisturbed soils. Aerobic incubation without theaddition of sugarcane residue led to a 21% decline in organanosulfur compounds directly linked to C and to up to an 82% increase inorganic S directly bonded to O. Among theC-bonded S compounds, low-valence thiols, sulfides, thiophenic S, and intermediate-valence sulfoxide S seem to be highly susceptible to microbial attack and may represent themost reactive components of organic S pool in these grassland soils. Sulfonate S exhibited a much lower shortterm reactivity. Th e incorporation of sugarcane residue resulted in an increase in organosulfur compounds directly bonded to C at theearly stage of incubation. However, similar to soils incubated without residue addition, theproportion of organic S directly linked to C continued to decline with increasing duration of aerobic incubation, whereas theproportion of organic S directly bonded to O showed a steady rise.
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U2 - 10.2134/jeq2010.0061
DO - 10.2134/jeq2010.0061
M3 - Article
C2 - 21546657
AN - SCOPUS:79956116576
SN - 0047-2425
VL - 40
SP - 704
EP - 718
JO - Journal of Environmental Quality
JF - Journal of Environmental Quality
IS - 3
ER -